Anyone with children has been in a situation where you'd love to get some good photos of your little darlings in the school play. Unfortunately, the last time you tried resulted in tiny faces barely recognizable. This was due to the distance and the fact that the flash didn't carry too well causing a weak, grainy enlargement.
Since you have to arrive early anyway, reserve a front row seat with a prepared sign and take a few snaps of your made-up, costumed kids behind the scenes using the props as a background. Snap a few full length photos and some closer up. If you have more than one or another player is available, have the children act out one of the skits (a highlight if possible). Medium shots of the actors interacting make great pictures. This should take only a few minutes if you work fast.
Nowadays, zoom telephoto lenses are commonly used on DSLR's and point and shoot cameras. Read the manual to find the longest distance effective with a fast (400 ISO) setting. An DSLR or EVF camera with a 200 mm lens at f 5.6 will probably be effective to thirty feet. A point and shoot with a 100 mm telephoto setting at f11 will only cover 10 or 12 feet to the subject. The most effective combination (and most expensive) is an APO 300mm f2.8 telephoto lens on an SLR with 400 ISO film. No flash would be necessary and higher shutterspeeds would be available (1/30 to 1/60 sec). An alternative would be a prosumer digital camera with lens or chip stabilization. Wide and medium angle shots should be metered on a face that fills the view finder and used for all exposures. If possible, set your camera for manual control of the f stop and shutter speed. Exposure readings of the stage at a distance will invariably over expose the faces by several f stops, making them appear faded out.
After the performance, be sure to capture those excited faces lit up by the tremendous applause with a few fast shots. Don't neglect yourself by handing off the camera to a friend for a picture with the kids. Finish up with some group photos of the actors and their friends. When the pictures come back, make two small albums with your favorite picture pasted on the front, one for you and one for your little stars!
In order to preserve your memories, you have to take the pictures.